NP, man. I don't perceive that they work less efficiently. With most grips, in fact, the inner area is hollowed out to enable installing or replacing the bearings, so you don't get as much contact area to the blade as you would otherwise; the washer-type spacers I've used spread the contact out on the blade and let it lead/lag more smoothly. I haven't used the folding TT original spacers, but they should be fine, too. Personally, I like having enough room to use washers around the blades.

I honestly don't know what blades would fit directly- I never went looking for them. If you're ok with spacers, the Align 325 woodies are good middle-of-the-road blades; they're pretty consistently made, they're dirt cheap, and if your local hobby shop carries any heli parts at all, they probably have these blades. They do have a sharp initial collective pop, but otherwise they're pretty smooth.